#include"mymath.h"
  int myerrno = 0;
int add(int x,int y)
{
 return x+y;
}
int  sub(int x,int y)
{
return x-y;
}
int mul(int x,int y)
{
return x*y;
}
int div(int x,int y)
{
	if(y==0)
	{
		myerrno = 1;
		return -1;
	}

	return x/y;
}
